This invention relates generally to an ornamental member produced by ion plating and more particularly to a multi-colored ornamental member formed of a combination of two hard films.
Conventional ornamental members, such as the exterior member of a watch with a multi-colored surface, include a stainless steel color and at least gold, dark grey, brown or blue. These generally are prepared by coating the surface of the ornamental member of a SUS material with a gold film produced by wet gold plating or ion plating, a dark grey film produced by wet rhodium or tin-nickel plating, or a brown film or a blue film produced by ion plating. A conventional exterior ornamental member of a watch with a two colored surface, including gold and brown or blue is generally produced by coating the surface of a substrate of the ornamental member with a gold film by gold or gold alloy wet plating and a brown or blue hard film produced by ion plating.
These conventional methods, however, suffer from poor scratch resistance, poor wear resistance and high cost. A partially exposed surface of a SUS material, which has a hardness of between about 140 and 180 Hv, is susceptible to scratching. A surface including a partial gold wet plated surface, which has a hardness of between about 200 and 300 Hv, is also susceptible to scratching. In order to enhance durability, it is necessary to increase the thickness of the layer of plating, which disadvantageously raises the cost of the article. A surface which is also partially wet plated with rhodium or tin-nickel is also susceptible to scratching. In addition, a rhodium plated surface is very expensive.
Accordingly, it is desirable to provide an improved ornamental member which eliminates these problems associated with the prior art and has good scratch resistance and wear resistance.